1. Field of the Invention
The invention relates to drive rings and, more particularly, relates to drive rings for transmitting torque from prime movers such as internal combustion engines to output elements such as power take-off shafts.
2. Discussion of the Related Art
Drive rings for transmitting rotational torque from prime movers such as gasoline or diesel engines and the like to output elements such as power take-off (PTO) shafts are well known. The typical drive ring is formed from a rigid metal material such as steel, is bolted or otherwise attached to the prime mover flywheel, and presents a relatively large number of relatively small internal metallic teeth which mate with external teeth of a drive plate. The drive plate may be coupled to an output element such as a shaft, or may be positively coupled to the output element.
The conventional drive ring having small metallic teeth exhibits several drawbacks and disadvantages. For instance, the metallic teeth are incapable of absorbing torsional vibrations which occur during operation of the drive train and which could damage or result in premature failure of the teeth on the drive ring and/or the drive plate. In addition, if the drive plate is a friction disc of a clutch, relative axial and/or radial movement between the drive plate and the drive ring causes the friction materials of the disc to abrade teeth of the drive ring. This abrasion leads to accelerated wear of the metallic drive ring teeth, thus leading to increased "chatter" and possibly to premature failure of the drive ring. The relatively small teeth on the drive ring and the drive plate also may be incapable of resisting the relatively high rotational shock loads which may be imposed on the mating teeth during operation of the system.